.NET Core应用如何通过SSL访问MongoDB？

大家好，我是Edison。

最近有一个ASP.NET Core通过SSL证书访问MongoDB的需求，但是在网上发现资料很少，于是调查了一番，做了如下的笔记，希望对你有用。

背景

在实际场景中，开发环境的MongoDB服务器一般没有要求通过SSL方式来登陆，但是生产环境的MongoDB服务器通常都会基于安全要求基于SSL方式来访问，这就要求客户端应用需要通过SSL证书来和MongoDB服务器进行通信验证后才能正常读取和写入数据。

那么，在ASP.NET Core应用中应该如何修改匹配呢？今天，我们就来看一看。

修改

通过学习MongoDB.Driver后，在实例化MongoClient时可以通过传递一个MongoClientSettings类来进行自定义参数的实例化，而这个MongoClientSettings类提供的参数比较丰富，我们可以将这些参数配置在appsettings中进行分环境的自定义。

var mongoClient = new MongoClient(new MongoClientSettings());

因此，我们可以写一个MongoSettings类来读取appsettings中的配置生成一个MongoClientSettings，这里给出一个参考示例。

using MongoDB.Driver;
using System.Security.Cryptography.X509Certificates;

namespace EDT.Todo.Data.Persistance
{
    /// <summary>
    /// Generate MongoClientSettings
    /// </summary>
    public class MongoSettings
    {
        public string Servers { get; set; }
        public int Port { get; set; } = 27017;
        public string ReplicaSetName { get; set; }
        public string DatabaseName { get; set; }
        public string DefaultCollectionName { get; set; } = string.Empty;
        public string ApplicationName { get; set; }
        public string UserName { get; set; }
        public string Password { get; set; }
        public string AuthDatabaseName { get; set; } = string.Empty;
        public string CustomProperties { get; set; } = string.Empty;
        public bool UseTLS { get; set; } = false;
        public bool AllowInsecureTLS { get; set; } = true;
        public string ClientCertificatePath { get; set; } = string.Empty;
        public bool StoreCertificateInKeyStore { get; set; } = false;

        public MongoClientSettings GetMongoClientSettings()
        {
            if (string.IsNullOrWhiteSpace(Servers))
                throw new ArgumentNullException("Mongo Servers Configuration is Missing!");

            if (string.IsNullOrWhiteSpace(UserName) || string.IsNullOrWhiteSpace(Password))
                throw new ArgumentNullException("Mongo Account Configuration is Missing!");

            // Base Configuration
            MongoClientSettings settings = new MongoClientSettings
            {
                ApplicationName = ApplicationName,
                ReplicaSetName = ReplicaSetName
            };

            // Credential
            if (string.IsNullOrWhiteSpace(AuthDatabaseName))
                settings.Credential = MongoCredential.CreateCredential(DatabaseName, UserName, Password);
            else
                settings.Credential = MongoCredential.CreateCredential(AuthDatabaseName, UserName, AuthDatabaseName);

            // Servers
            var mongoServers = Servers.Split(",", StringSplitOptions.RemoveEmptyEntries).ToList();
            if (mongoServers.Count == 1)
            {
                settings.Server = new MongoServerAddress(mongoServers.First(), Port);
                settings.DirectConnection = true;
            }

            if (mongoServers.Count > 1)
            {
                var mongoServerAddresses = new List<MongoServerAddress>();
                foreach (var mongoServer in mongoServers)
                {
                    var mongoServerAddress = new MongoServerAddress(mongoServer, Port);
                    mongoServerAddresses.Add(mongoServerAddress);
                }
                settings.Servers = mongoServerAddresses;
                settings.DirectConnection = false;
            }

            // SSL
            if (UseTLS)
            {
                settings.UseTls = true;
                settings.AllowInsecureTls = AllowInsecureTLS;
                if (string.IsNullOrWhiteSpace(ClientCertificatePath))
                    throw new ArgumentNullException("ClientCertificatePath is Missing!");
                var certs = new List<X509Certificate> { new X509Certificate2(ClientCertificatePath) };
                settings.SslSettings = new SslSettings();
                settings.SslSettings.ClientCertificates = certs;
                settings.SslSettings.EnabledSslProtocols = System.Security.Authentication.SslProtocols.Tls13;
            }

            return settings;
        }
    }
}

对于原有的Repository类，我们则需要做一点点修改，从IoC容器中获取MongoSettings的实例，并通过调用GetMongoClientSettings方法获取到生成的这个具体的MongoClientSettings对象：

public class TodoItemRepository : ITodoItemRepository
{
    private readonly ILogger<TodoItemRepository> _logger;
    private readonly IMongoCollection<TodoItem> _todoItems;

    public TodoItemRepository(MongoSettings settings, ILogger<TodoItemRepository> logger)
    {
        var mongoClient = new MongoClient(settings.GetMongoClientSettings());
        var mongoDatabase = mongoClient.GetDatabase(settings.DatabaseName);
        _todoItems = mongoDatabase.GetCollection<TodoItem>(settings.DefaultCollectionName);
        _logger = logger;
    }
    
    ......
}

在Program.cs中将MongoSettings和appsettings中的配置绑定：

builder.Services.Configure<MongoSettings>(
    builder.Configuration.GetSection("MongoDatabase"));
builder.Services.AddSingleton(sp =>
    sp.GetRequiredService<IOptions<MongoSettings>>().Value);
......
builder.Services.AddSingleton<ITodoItemRepository, TodoItemRepository>();

针对Development环境的appsettings：

{
  ......   
  "MongoDatabase": {
    "Servers": "dev.mongodb01.com,dev.mongodb01.com,dev.mongodb01.com",
    "Port": 27017,
    "ReplicaSetName": "testrplica",
    "DatabaseName": "TestDB",
    "DefaultCollectionName": "TodoItems",
    "ApplicationName": "Todo",
    "UserName": "dev_mongo_user",
    "Password": "passwordfordevuser",
    "UseTLS": false
  }
}

针对Production环境的appsettings：

{
  ......   
  "MongoDatabase": {
    "Servers": "prd.mongo01.com,prd.mongo02.com,prd.mongo03.com",
    "Port": 27007,
    "ReplicaSetName": "testreplica",
    "DatabaseName": "TestDB",
    "DefaultCollectionName": "TodoItems",
    "ApplicationName": "Todo",
    "UserName": "prd_mongo_user",
    "Password": "passwordforprduser",
    "UseTLS": true,
    "AllowInsecureTLS": true,
    "ClientCertificatePath": "resources/certificates/intranet_server_ca.cer"
  }
}